Daily high temperatures increase by 2°F, from 76°F to 78°F, rarely falling below 72°F or exceeding 84°F.
Daily low temperatures increase by 2°F, from 63°F to 65°F, rarely falling below 60°F or exceeding 69°F.
For reference, on August 26, the hottest day of the year, temperatures in Westmont typically range from 66°F to 80°F, while on December 28, the coldest day of the year, they range from 49°F to 66°F.
Average High and Low Temperature in July
The daily average high (red line) and low (blue line) temperature, with 25th to 75th and 10th to 90th percentile bands. The thin dotted lines are the corresponding average perceived temperatures.
The figure below shows you a compact characterization of the hourly average temperatures for the quarter of the year centered on July. The horizontal axis is the day, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.
Average Hourly Temperature in July
The average hourly temperature, color coded into bands: frigid < 15°F < freezing < 32°F < very cold < 45°F < cold < 55°F < cool < 65°F < comfortable < 75°F < warm < 85°F < hot < 95°F < sweltering. The shaded overlays indicate night and civil twilight.
The month of July in Westmont experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 11% throughout the month.
The clearest day of the month is July 31, with clear, mostly clear, or partly cloudy conditions 90% of the time.
For reference, on February 20, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 42%, while on September 7, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 91%.
Cloud Cover Categories in July
The percentage of time spent in each cloud cover band, categorized by the percentage of the sky covered by clouds: clear < 20% < mostly clear < 40% < partly cloudy < 60% < mostly cloudy < 80% < overcast.
Over the course of July in Westmont, the length of the day is decreasing. From the start to the end of the month, the length of the day decreases by 32 minutes, implying an average daily decrease of 1 minute, 4 seconds, and weekly decrease of 7 minutes, 27 seconds.
The shortest day of the month is July 31, with 13 hours, 51 minutes of daylight and the longest day is July 1, with 14 hours, 22 minutes of daylight.
Hours of Daylight and Twilight in July
The number of hours during which the Sun is visible (black line). From bottom (most yellow) to top (most gray), the color bands indicate: full daylight, twilight (civil, nautical, and astronomical), and full night.
The earliest sunrise of the month in Westmont is 5:45 AM on July 1 and the latest sunrise is 18 minutes later at 6:04 AM on July 31.
The latest sunset is 8:08 PM on July 1 and the earliest sunset is 14 minutes earlier at 7:54 PM on July 31.
Daylight saving time is observed in Westmont during 2018, but it neither starts nor ends during July, so the entire month is in daylight saving time.
For reference, on June 21, the longest day of the year, the Sun rises at 5:42 AM and sets 14 hours, 25 minutes later, at 8:07 PM, while on December 21, the shortest day of the year, it rises at 6:54 AM and sets 9 hours, 54 minutes later, at 4:48 PM.
Sunrise & Sunset with Twilight in July
The solar day over the course of July. From bottom to top, the black lines are the previous solar midnight, sunrise, solar noon, sunset, and the next solar midnight. The day, twilights (civil, nautical, and astronomical), and night are indicated by the color bands from yellow to gray.
We base the humidity comfort level on the dew point, as it determines whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid. Unlike temperature, which typically varies significantly between night and day, dew point tends to change more slowly, so while the temperature may drop at night, a muggy day is typically followed by a muggy night.
The chance that a given day will be muggy in Westmont is increasing during July, rising from 2% to 8% over the course of the month.
For reference, on August 4, the muggiest day of the year, there are muggy conditions 8% of the time, while on January 1, the least muggy day of the year, there are muggy conditions 0% of the time.
Humidity Comfort Levels in July
The percentage of time spent at various humidity comfort levels, categorized by dew point: dry < 55°F < comfortable < 60°F < humid < 65°F < muggy < 70°F < oppressive < 75°F < miserable.
This section discusses the wide-area hourly average wind vector (speed and direction) at 10 meters above the ground. The wind experienced at any given location is highly dependent on local topography and other factors, and instantaneous wind speed and direction vary more widely than hourly averages.
The average hourly wind speed in Westmont is essentially constant during July, remaining within 0.2 miles per hour of 5.4 miles per hour throughout.
For reference, on December 31, the windiest day of the year, the daily average wind speed is 8.7 miles per hour, while on August 13, the calmest day of the year, the daily average wind speed is 5.1 miles per hour.
Average Wind Speed in July
The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.
The hourly average wind direction in Westmont throughout July is predominantly from the west, with a peak proportion of 45% on July 3.
Wind Direction in July
The percentage of hours in which the mean wind direction is from each of the four cardinal wind directions (north, east, south, and west), excluding hours in which the mean wind speed is less than 1 mph. The lightly tinted areas at the boundaries are the percentage of hours spent in the implied intermediate directions (northeast, southeast, southwest, and northwest).
Westmont is located near a large body of water (e.g., ocean, sea, or large lake). This section reports on the wide-area average surface temperature of that water.
The average surface water temperature in Westmont is gradually increasing during July, rising by 2°F, from 66°F to 68°F, over the course of the month.
Average Water Temperature in July
The daily average water temperature (purple line), with 25th to 75th and 10th to 90th percentile bands.
Definitions of the growing season vary throughout the world, but for the purposes of this report, we define it as the longest continuous period of non-freezing temperatures (≥ 32°F) in the year (the calendar year in the Northern Hemisphere, or from July 1 until June 30 in the Southern Hemisphere).
Temperatures in Westmont are sufficiently warm year round that it is not entirely meaningful to discuss the growing season in these terms. We nevertheless include the chart below as an illustration of the distribution of temperatures experienced throughout the year.
Time Spent in Various Temperature Bands and the Growing Season in July
The percentage of time spent in various temperature bands: frigid < 15°F < freezing < 32°F < very cold < 45°F < cold < 55°F < cool < 65°F < comfortable < 75°F < warm < 85°F < hot < 95°F < sweltering. The black line is the percentage chance that a given day is within the growing season.
Growing degree days are a measure of yearly heat accumulation used to predict plant and animal development, and defined as the integral of warmth above a base temperature, discarding any excess above a maximum temperature. In this report, we use a base of 50°F and a cap of 86°F.
The average accumulated growing degree days in Westmont are rapidly increasing during July, increasing by 596°F, from 2,048°F to 2,644°F, over the course of the month.
Growing Degree Days in July
The average growing degree days accumulated over the course of July, with 25th to 75th and 10th to 90th percentile bands.
This section discusses the total daily incident shortwave solar energy reaching the surface of the ground over a wide area, taking full account of seasonal variations in the length of the day, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. Shortwave radiation includes visible light and ultraviolet radiation.
The average daily incident shortwave solar energy in Westmont is essentially constant during July, remaining within 0.2 kWh of 8.2 kWh throughout.
Average Daily Incident Shortwave Solar Energy in July
The average daily shortwave solar energy reaching the ground per square meter (orange line), with 25th to 75th and 10th to 90th percentile bands.
For the purposes of this report, the geographical coordinates of Westmont are 33.941 deg latitude, -118.302 deg longitude, and 135 ft elevation.
The topography within 2 miles of Westmont contains only modest variations in elevation, with a maximum elevation change of 197 feet and an average elevation above sea level of 159 feet. Within 10 miles contains only modest variations in elevation (610 feet). Within 50 miles contains significant variations in elevation (10,062 feet).
The area within 2 miles of Westmont is covered by artificial surfaces (99%), within 10 miles by artificial surfaces (91%), and within 50 miles by water (38%) and shrubs (29%).
This report illustrates the typical weather in Westmont year round, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016.
Temperature and Dew Point
There are 3 weather stations near enough to contribute to our estimation of the temperature and dew point in Westmont.
The estimated value at Westmont is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Westmont and a given station.
All other weather data, including cloud cover, precipitation, wind speed and direction, and solar flux, come from NASA's MERRA-2 Modern-Era Retrospective Analysis . This reanalysis combines a variety of wide-area measurements in a state-of-the-art global meteorological model to reconstruct the hourly history of weather throughout the world on a 50-kilometer grid.
The information on this site is provided as is, without any assurances as to its accuracy or suitability for any purpose. Weather data is prone to errors, outages, and other defects. We assume no responsibility for any decisions made on the basis of the content presented on this site.
We draw particular cautious attention to our reliance on the MERRA-2 model-based reconstructions for a number of important data series. While having the tremendous advantages of temporal and spatial completeness, these reconstructions: (1) are based on computer models that may have model-based errors, (2) are coarsely sampled on a 50 km grid and are therefore unable to reconstruct the local variations of many microclimates, and (3) have particular difficulty with the weather in some coastal areas, especially small islands.
We further caution that our travel scores are only as good as the data that underpin them, that weather conditions at any given location and time are unpredictable and variable, and that the definition of the scores reflects a particular set of preferences that may not agree with those of any particular reader.